docs: def read_vs30(fnames):
      """
      :param fnames: a list of CSV files with fields lon,lat,vs30
      :returns: a vs30 array of dtype vs30dt
      """
      data = []
      for fname in fnames:
          for line in open(fname, encoding='utf-8-sig'):
              data.append(tuple(line.split(',')))
      return numpy.array(data, vs30_dt)